Welcome to the Let's Preserve blog! Brought to you by Penn State Cooperative Extension, you will find the latest on preserving safe, high quality food at home. The information included is based on up-to-date research from the U.S. Dept of Agriculture and Cooperative Extension.

Tuesday, August 17, 2010

Blanching Vegetables is a Must Before Freezing

If you hope to pull tasty, nutritious vegetables from your freezer next winter, you need to blanch them first. Blanching stops the action of enzymes. These naturally occur in vegetables helping them grow and ripen. The enzymes continue to act after harvest and will cause color, flavor, texture, and nutrient losses. Freezing slows down the action of enyzmes, but does not stop them.

A good example of what happens when vegetables are not blanched before freezing was shared by a participant in a freezing class. She encouraged me to share her story. To use her words, she had a "freezer full" of green beans that she froze without blanching. When she went to use some she found them mushy and flavorless and not anything she wanted to eat or serve. All her time and efforts, expense of freezer bags and electricity for the freezer, and she had to throw the beans away!

Blanching also removes air and helps vegetables to shrink so they take up less freezer space. Plant and pesticide residues and microorganisms are removed from vegetable surfaces. Peels that need removing are loosened. Blanching will actually brighten the color of vegetables.

Blanching in boiling water is the best way to blanch vegetables. Steam blanching works well for broccoli, pumpkin, sweet potatoes, and winter squash. Microwave blanching is not recommended.

It is important to follow blanching directions precisely. Timing is crucial. Over blanching will cause vegetables to start cooking and quality will be lost. Underblanching has been found to stimulate enzyme activity and is worse than no blanching at all.

There is no "one time fits all" for blanching. Time will vary depending on the vegetable and its size. Blanching times and steps for water and steam blanching can be found at http://www.uga.edu/nchfp/how/freeze/blanching.html.

A few tips for success in blanching:
  • Use a blancher which has a blanching basket and cover, or fit a wire basket into a large pot with a lid.

  • Use one gallon water per pound of vegetables when water blanching.

  • Blanch vegetables in small batches. After adding vegetables to boiling water and putting lid on pot, water should return to boil within one minute. If it doesn't you are using too much vegetable for the amount of boiling water.

  • For water blanching start counting blanching time as soon as water returns to a boil. For steam blanching start counting time as soon as lid is on pot.

  • Cool blanched vegetables quickly to stop cooking. Plunge basket into very cold water and change the water frequently, or use ice water. If ice is used to cool you will need about one pound ice per pound of vegetables.

  • Vegetables should cool in about the same amount of time as they were blanched.

  • Drain vegetables well after cooling since extra moisture can cause loss of quality when vegetables are frozen.

  • Once cooled and drained, quickly move vegetables to freezer container and put into freezer.

As with many "rules" there is often an exception. It is okay to freeze onions, sweet and hot peppers, and raw tomatoes without blanching. Visit the following link at the University of Nebraska-Lincoln Extension for directions on freezing onions. This link will give links to freezing peppers and tomatoes. http://lancaster.unl.edu/food/ciq-onions.shtml.

Friday, August 6, 2010

Acidify Your Tomatoes Before Canning

Most of us think of tomatoes as acid food. However, with home canning, the acid level, or pH, of tomatoes is very close to the borderline for being considered low-acid. Low-acid foods like vegetables and meats need to be processed in the pressure canner to be safe.

As a measure of safety, experts recommend that home canned tomatoes that are typically processed in the boiling water canner be acidified. This includes whole, crushed and juiced tomatoes, and tomatillos. Recipes for these products will sometimes have directions for processing in the boiling water canner and pressure canner. The product should still be acidified even if processed in the pressure canner.

Bottled lemon juice or citric acid can be used to acidify tomatoes. Use the following proportions of acid:

Lemon juice
per quart - 2 tablespoons
per pint - 1 tablespoon

Citric acid
per quart - 1/2 teaspoon
per pint - 1/4 teaspoon

Add the acid directly to the jar before adding the product. A small amount of sugar can be added to offset an acid taste.

Be sure to use bottled lemon juice not fresh. The bottled juice has a standardized acid level, but fresh may vary. Citric acid is usually found where canning supplies are sold.

Vinegar of 5% acidity can be used instead of lemon juice or citric acid. Use four tablespoons of vinegar per quart or two tablespoons per pint. However, vinegar may cause undesirable changes in flavor so lemon juice or citric acid is preferred.

Visit the National Center for Home Food Preservation for up-to-date recipes for canning tomato products, including salsas. http://www.uga.edu/nchfp/how/can3_tomato.html

Wednesday, August 4, 2010

Reducing the Salt in Home Canned Foods

Health experts tell us that many Americans are eating too much salt. Salt is a mix of sodium and chloride and it is the sodium portion that can cause problems. Too much sodium in the diet can encourage high blood pressure in some people.

Interestingly, when I first started working in the nutrition field about 30 years ago most of the salt in our diets came from what we added to food when cooking and eating. Today, this has changed, with a greater portion coming from processed foods.

Salt can be left out of most home canned foods and you will still have a safe product. Recipes for canning meats, poultry, fish, vegetables, and tomato products include salt for flavoring, not preserving.

An exception to this is when making fermented products, like pickles and sauerkraut. Don't leave out or adjust the amount of salt. Proper fermentation depends on correct proportions of salt and other ingredients. Changing the amount of salt in these recipes will make an unsafe product, and it will likely spoil.

Fresh pack pickles, cucumbers that are acidified quickly with vinegar, can be made with reduced or no salt. Only tested recipes should be used. Fresh pack pickles will be safe with the salt reduced, however, their texture and flavor may not be as good.

USDA's Complete Guide to Home Canning has recipes for reduced-sodium sliced dill and sweet pickles. You will find these at http://www.uga.edu/nchfp/how/diet_pick.html.

When using salt in home canned foods use pure granulated salt such as canning or pickling salt. Other salts have anti-caking ingredients which may cause the liquid to become cloudy. Flaked salt varies in density and should not be used for pickling. To read more go to http://extension.psu.edu/food-safety/food-preservation/faq/canning-and-pickling-salt.